Aims: To explore whether awake and sleep bruxism interact in their associations with painful temporomandibular disorders (TMD) and whether the interaction is multiplicative or additive. Methods: In this case-control study, all participants (n = 705) were part of the multicenter Validation Project and were recruited as a convenience sample of community cases and controls and clinic cases. Logistic regression analyses were applied to test for the association between self-reported bruxism (sleep and/or awake) and the presence of painful TMD, and odds ratios (ORs) with 95% confidence intervals (95% CIs) were computed. Regression models included an interaction term to test for multiplicative interaction, and additive interaction was calculated as the relative excess risk due to interaction (RERI). Results: Based on logistic regression analyses adjusted for age and gender, the main effects for both awake (OR = 6.7; 95% CI: 3.4 to 12.9) and sleep (OR = 5.1; 95% CI: 3.1 to 8.3) bruxism were significant. While the multiplicative interaction (OR = 0.57; 95% CI: 0.24 to 1.4) was not significant, the results indicated a significant positive additive interaction (RERI = 8.6; 95% CI: 1.0 to 19.7) on the OR scale. Conclusion: This study has demonstrated that awake and sleep bruxism are associated with an increased presence of painful TMD, and that both types of bruxism are not independently associated, but interact additively. As such, the presence of each factor amplifies the effect of the other.

Aims: To use the Symptom Checklist-90-Revised (SCL-90-R)-based instruments of the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) and the Primary Care Evaluation of Mental Disorders (PRIME-MD)- based instruments of the Diagnostic Criteria for Temporomandibular Disorders (DC/TMD) in order to compare these Axis II scores in temporomandibular disorder (TMD) patients. Methods: Demographic and socioeconomic data, Axis I diagnoses, and Axis II evaluations (depression, nonspecific physical symptoms, anxiety, and Graded Chronic Pain Scale [GCPS]) were compared between two groups of patients-142 TMD patients diagnosed according to the RDC/TMD (RDC group) and 157 TMD patients diagnosed according to the DC/TMD (DC group). Pearson's chi-square test, Fisher's exact test, and Mann-Whitney test were used, and P values were adjusted for multiple comparisons. Results: The prevalences of severe depression, nonspecific physical symptoms, and anxiety were significantly lower in the DC group than in the RDC group, with no differences between groups for Axis I diagnoses, characteristic pain intensity (CPI), or GCPS. Conclusion: Within the limitations of this study, the present findings reveal differences in the presence of severe depression, nonspecific physical symptoms, and anxiety between the RDC and DC groups. The differences may reflect the cut-off scores of the SCL-90-R and the PRIME-MD tools.

Aims: To investigate whether pain-related temporomandibular disorders (TMD) are the product of an interaction between psychological factors and self-reported bruxism activities. Methods: Patients referred to a specialized clinic for complaints of orofacial pain and dysfunction completed a digital questionnaire prior to the first clinical visit. The patient sample was then split into a case group consisting of 268 patients diagnosed with TMD pain according to the Diagnostic Criteria for Temporomandibular Disorders (85.8% women; mean ± standard deviation [SD] age = 40.1 ± 14.5 years) and a control group consisting of 254 patients without any pain in the orofacial area (50.8% women; 46.9 ± 13.6 years). The possible moderating roles of six psychological factors (depression, somatic symptoms, anxiety, stress, optimism, and prior psychological treatment) on the relationship between selfreported bruxism and the clinical presence of TMD pain were examined. Results: Patients with TMD pain reported significantly more bruxism than patients without any report of orofacial pain. Furthermore, bruxism intensity was associated with a variety of psychological factors; however, there were no significant interactions between any of the psychological factors and bruxism with respect to the clinical presence of TMD pain. Conclusion: These findings do not support the view that the effect of bruxism on TMD pain is stronger in patients who experience higher levels of psychological distress compared to those with lower levels of distress.

Aims: To prospectively assess the incidence and etiology (ie, primary vs symptomatic) of headache in women during the first month postdelivery, with particular emphasis on the type of presentation as a clue for identifying potentially harmful etiologies. A secondary aim was to evaluate the relative frequency of migraine- vs tension-type headache in cases of primary headache. Methods: A total of 900 consecutive women were enrolled in the study and examined within 3 days of delivery, both clinically and with transcranial color-coded sonography (TCCS). During the course of follow-up, all subjects presenting with headache suspected of being secondary to intracranial pathology underwent a complete clinical and instrumental assessment with TCCS and magnetic resonance imaging (MRI) and angiography. A telephone interview was administered to all subjects 1 month after delivery. Two-tailed t test, Mann-Whitney test, Pearson chi-square test, and multiple logistic regression were used to analyze the data. Results: At the end of the follow-up period, 241 women (26.8% of the sample) reported at least one headache attack. In 88 of these 241 cases (9.8%), the headache attack occurred soon after delivery and was already recorded at the first visit. Thunderclap headache occurred in 34 (3.8%) of the subjects. In all but one of these subjects, the course was spontaneously benign. None of the recorded variables allowed discrimination of the subjects with thunderclap headache from those without headache. Three subjects had thunderclap headache following dural anesthesia, and one subject was found to have reversible cerebral vasoconstriction syndrome. Headache with gradual onset was recorded in 207 subjects (23%). Three of these subjects fulfilled the criteria for pre-eclampsia, and 13 had postural headache after dural anesthesia. Migraine history and urinary protein were independent predictors of gradual onset headache, and migraine history and parity were significant independent predictors of pulsating pain with gradual onset headache. Conclusion: Headache appeared early in the first days postdelivery, and its incidence increased in the first month thereafter. Predictors were different according to whether the headache had a gradual onset or a thunderclap presentation. Primary headache accounted for the overwhelming majority of the recorded cases.

Aims: To deepen knowledge of how parents of children diagnosed with juvenile idiopathic arthritis (JIA) perceive the orofacial manifestations of the disease, its treatments, and their encounters with dental care providers. Methods: A total of 15 interviews with parents of JIA patients (3 to 16 years old) with orofacial pain were analyzed according to classic grounded theory. Results: The main problem was identified as controlling an unpredictable life situation that includes a child with JIA. To solve this main problem, the parent was trying to comprehend, help, and speak for the child with disability, a solution that permeated their life situation. This was therefore identified as the core category, and the other categories (ie, ways parents responded to their situation) were reflecting on and re-evaluating the life situation, monitoring the child's symptoms and treatments, adapting everyday routines, seeking doctors and information, influencing school and society, and managing job and family finances. The main problem and the various categories formed a model reflecting how parents of children diagnosed with JIA act and think. Conclusion: It is extremely important for caregivers to understand the complexity of the life situation for parents whose children have been diagnosed with JIA. They must facilitate the parent's understanding of how this disease can influence the orofacial area and day-to-day care.

Aims: To assess the diversity of pressure pain thresholds (PPTs) within the masseter and temporalis muscles by using the novel concept of entropy and to assess the differences in PPT scores between different sites of the masseter and temporalis muscles. Methods: In this randomized, single-blinded study, the left and right masseter and temporalis muscles of 14 healthy volunteers were divided into 15 sites each, and the PPT was assessed for each of these sites. PPT assessments were performed in two different sessions. Entropy and center of gravity (COG) values were calculated for the PPTs of each muscle. Repeated measures analysis of variance was used to assess differences between muscles, sides, and sites for PPT, entropy, and COG scores. Results: The main findings were: (1) PPT scores varied significantly between the masseter and temporalis muscles and within each of these muscles; (2) entropy values of PPT scores were not different between the masseter and temporalis muscles; and (3) COG values of PPT scores varied statistically, but these changes do not seem to be clinically relevant. Conclusion: The results of this study suggest that the anatomical layout of the masseter and temporalis muscles has implications for mechanical pain sensitivity and that areas have different sensitivities within these muscles. Furthermore, reference values for the entropy of PPTs in healthy individuals have been estimated, and comparing these values with those of patients with muscle-related pain conditions can provide quantitative information about the spatial heterogeneity of mechanical pain sensitivity, which may be a valuable clinical outcome measure.

Aims: To develop a tongue pain model with no mucosal pathologic changes and to examine whether phosphorylation of p38 in trigeminal ganglion (TG) neurons innervating the tongue is associated with tongue heat hypersensitivity in mice. Methods: Tongue heat sensitivity in mice was assessed following application of the irritant 2,4,6-trinitrobenzene sulfonic acid (TNBS) to the tongue. After TNBS application, the expressions of p38, phosphorylated p38 (pp38), and transient receptor potential vanilloid 1 (TRPV1) were examined in TG neurons innervating the tongue. To further assess changes in tongue heat sensitivity and TRPV1 expression, a specific inhibitor of p38 phosphorylation (SB203580) was also administered into the TG. Student t test or two-way repeated-measures analysis of variance followed by Sidak multiple comparison test were used for statistical analysis, and P < .05 was considered statistically significant. Results: TNBS application to the tongue induced noninflammatory heat hypersensitivity accompanied by the enhancement of p38 phosphorylation in TG neurons innervating the tongue and by an increase in the number of TRPV1 and pp38- immunoreactive (IR) TG neurons innervating the tongue. Intra-TG administration of SB203580 suppressed the increase in the TRPV1 and pp38-IR TG neurons and alleviated the noninflammatory tongue heat hypersensitivity induced by TNBS. Conclusion: p38 signaling cascades are involved in tongue heat hyperalgesia in association with TRPV1 upregulation in TG neurons innervating the TNBS-treated tongue.

Aims: To investigate the effects and interactions of sex and stress (provoked by chronic restraint [RS]) on pain-like behavior in a rat model of trigeminal neuropathic pain. Methods: The effects of sex and RS (carried out for 14 days as a model for stress) on somatosensory measures (reaction to pinprick, von Frey threshold) in a rat model of trigeminal neuropathic pain were examined. The study design was 2 × 4, with surgery (pain) and sham surgery (no pain) interacting with male restrained (RS) and unrestrained (nRS) rats and female RS and nRS rats. A total of 64 Sprague Dawley rats (32 males and 32 females) were used. Half of the animals in each sex group underwent RS, and the remaining half were left unstressed. Following the RS period, trigeminal neuropathic pain was induced by unilateral infraorbital nerve chronic constriction injury (IOCCI). Half of the animals in the RS group and half in the nRS group (both males and females) were exposed to IOCCI, and the remaining halves to sham surgery. Elevated plus maze (EPM) assessment and plasma interferon gamma (IFN-γ) levels were used to measure the effects of RS. Analysis of variance (ANOVA) was used to assess the effects of stress, sex, and their interactions on plasma IFN-γ levels, changes in body weight, EPM parameters, tactile allodynia, and mechanohyperalgesia. Pairwise comparisons were performed by using Tukey post hoc test corrected for multiple comparisons. Results: Both male and female RS rats showed significantly altered exploratory behavior (as measured by EPM) and had significantly lower plasma IFN-γ levels than nRS rats. Rats exposed to RS gained weight significantly slower than the nRS rats, irrespective of sex. Following RS but before surgery, RS rats showed significant bilateral reductions in von Frey thresholds and significantly increased pinprick response difference scores compared to nRS rats, irrespective of sex. From 17 days postsurgery, RSIOCCI rats showed significantly reduced von Frey thresholds and significantly increased pinprick response difference scores compared to nRS-IOCCI rats, and the von Frey thresholds were significantly lower in females than in males. RS-sham females-but not RS-sham males-developed persistently reduced thresholds and increased pinprick response difference scores. Conclusion: RS produced an increased bilateral sensitivity to stimuli applied to the vibrissal pad following infraorbital nerve injury, irrespective of sex. This observed sensitivity subsequently persisted in RS-sham female rats but not in RS-sham male rats. Stress induced a significant but moderate increase in pain-like behavior in female rats compared to male rats. RS had no significant sex effects on IFN-γ levels, EPM parameters, or body weight gain. This suggests that stress may have a selective effect on pain-like behavior in both sexes, but the possible mechanisms are unclear.

Epicrania fugax (EF) was recently classified as a primary headache in the Appendix of the International Classification of Headache Disorders, third edition (ICHD-III). It is characterized by a paroxysmal pain rapidly radiating forward or backward along a linear or zigzag trajectory on the surface of the head. This article reports a 76-year-old woman who newly developed a paroxysmal EF-type pain distributed not only in the territories of the trigeminal and occipital nerves, but also in the territories of the cervical and thoracic nerves. This EF-type pain started in a point on the prethoracic area, radiated along the ipsilateral neck, face, auditory canal, and head surface in a linear trajectory, and finally initiated attacks of nervus intermedius neuralgia (NIN) and migraine without aura (MWA). Treatment with a low dose of carbamazepine was associated with decreased intensity of EF-type pain and fewer NIN and MWA attacks, while a higher dose of carbamazepine was associated with complete termination of EF-type pain and NIN and MWA attacks. This case report expands the clinical spectrum of EF and may also be helpful in understanding its pathophysiology.

Neurofibromatosis type 1 (NF-1) is a genetic disease with characteristic neurofibromas and bony dysplasia that manifest throughout the body, including the craniofacial region. NF-1 patients are known to frequently report chronic pain in areas below the head; however, the matter of pain in the craniofacial region in this patient group has not been handled intensively so far, and studies have mainly focused on headaches. This article comprehensively reviews the related literature and reports a case of an NF-1 patient whose chief complaint was headache and pain in the temporomandibular joint area. Craniofacial pain is probably not an exceptional problem in NF-1, but the current inadequacy of related data is worrisome, considering the impact of pain on NF-1 prognosis and patient quality of life. The presence of craniofacial pain in NF-1 patients should be actively sought out in the diagnostic process and appropriate guidelines for its diagnosis and treatment should be established.

The primary symptom of ischemic heart disease is typically chest pain, but in some cases, this pain may radiate to the maxillofacial region. This article describes the case of a 44-year-old man with orofacial pain of cardiac origin. The patient was suspected to be suffering from cardiac disease by the oral and maxillofacial surgeon and was referred to a cardiologist, where he received a heart examination. The patient was diagnosed by means of cardiac catheterization as having coronary spastic angina. During catheterization, intracoronary ergonovine maleate induced orofacial pain that was almost the same in character and intensity as the patient's first episode. The orofacial pain was considered to be telalgia from coronary spastic angina. The patient started medication on the same day as the diagnosis. There was no recurrence of any symptoms. These findings indicate that in such cases, the dentist may contribute to identifying ischemic heart disease and should refer the patient to a cardiologist.

Although several reports have indicated that trigeminal neuralgia related to multiple sclerosis may occur bilaterally in the orofacial region, trigeminal neuralgia pain usually involves the two sides in different time lapses, and the simultaneous involvement of trigeminal territories on both sides is commonly considered incompatible with its diagnosis. This case report describes a patient with bilateral trigeminal neuralgia related to multiple sclerosis that started simultaneously on both sides of the orofacial region. A 55-year-old man presented with a 16-year history of relapsing/remitting multiple sclerosis. For 1 year, the patient had been complaining of electric shock-like, paroxysmal pain of severe intensity that lasted from a fraction of a second to a few minutes and involved the first and second trigeminal divisions of both sides simultaneously. The neurophysiologic testing of trigeminal reflexes showed bilateral delayed latencies of reflex responses compatible with a trigeminal afferent pathway impairment related to multiple sclerosis. A dedicated 3T magnetic resonance imaging scan revealed pontine demyelinating plaque and a bilateral neurovascular conflict at the trigeminal root entry zone. The finding of an unusual case of simultaneous bilateral trigeminal neuralgia due to multiple sclerosis should prompt neurologists to consider a diagnosis of trigeminal neuralgia in patients with multiple sclerosis in cases of simultaneous involvement of trigeminal territories on both sides.

Lightning and other electrical incidents are responsible for more than 300 injuries and 100 deaths per year in the United States alone. Lightning strikes can cause a wide spectrum of neurologic manifestations affecting any part of the neuraxis through direct strikes, side flashes, touch voltage, connecting leaders, or acoustic shock waves. This article describes the first case of trigeminal neuralgia induced by lightning injury to the trigeminal nerve, thereby adding a new syndrome to the list of possible lightning-mediated neurologic injuries.

This article reports a case of a cerebellopontine angle epidermoid cyst presenting as isolated painful trigeminal neuropathy. The indolent nature of these uncommon benign tumors leads to frequent delays in their presentation and diagnosis, with patients often initially undergoing dental procedures. This is illustrated in the present case reported here, which highlights the difficulties in identifying trigeminal neuralgia (TN), particularly in its early phases, and supports current recommendations for routine neuroimaging in suspected cases of painful trigeminal neuropathy, which, unlike classic TN, is caused by a disorder other than neurovascular compression (even in the absence of additional neurologic symptoms or signs) and is present particularly in younger patients with atypical features. Additionally, this case report offers a unique patient perspective of living with TN, with a detailed description by one of the authors of the nature of the pain and its impact.

Aims: To describe the clinical characteristics of trigeminal neuralgia (TN) in a multi-ethnic Malaysian population and to relate them to standardized measures of pain severity, anxiety, depression, and quality of life (QoL). Methods: Patients fulfilling the International Headache Society (IHS) criteria for TN were prospectively interviewed for their demographic and clinical data. Pain intensity was rated with a visual analog scale (VAS), anxiety and depression were determined by the Hospital Anxiety and Depression Scale (HADS), and QoL was assessed by the Short-Form 36 (SF-36) questionnaire. Chi-square, Mann- Whitney U, and Spearman correlation tests were used to test for differences considering a significance level of P < .05. Results: Of the 75 included patients, 52 (69.3%) were women with a mean ± standard deviation (SD) onset age of 52.0 ± 12.7 years, and 57.3% were Chinese, 24.0% Malay, and 18.7% Indian. Pain was more common on the right side (69.3%) and in the maxillary and mandibular divisions. VAS scores for pain at its worst were higher in anxious/ borderline anxious patients compared to non-anxious patients (89.5 ± 15.9 vs 80.9 ± 17.2, respectively; P < .05), and VAS scores for pain at its least were higher in depressed/borderline depressed subjects compared to non-depressed subjects (38.4 ± 25.8 vs 23.0 ± 19.2, respectively; P < .05). Chinese patients had lower VAS scores for pain at its least compared to Indian patients (19.7 ± 16.1 vs 39.9 ± 24.7; P < .01). TN patients scored lower in all eight domains of the SF-36 compared to the general population. Indian patients had lower scores in role limitations due to physical health (8.9 ± 23.2 vs 49.4 ± 43.8; P < .01) and social function (56.3 ± 13.6 vs 76.5 ± 23.6; P < .01) than Chinese patients, and Malay patients had lower mental health scores compared to Chinese patients (59.1 ± 19.5 vs 73.0 ± 21.0; P < .01). Conclusion: Clinical characteristics of TN patients were similar to those of other populations. There were differences in pain ratings and QoL between TN patients of different ethnicities, as well as between those with anxiety and depression.

Aims: To determine the effect of articaine on sarcoendoplasmic reticulum calcium adenosine triphosphatase (SERCA) isoforms of the medial pterygoid muscle. Methods: Native SERCA from the medial pterygoid muscles of 24 rabbits was isolated by ultracentrifugation, and its isoforms were purified by chromatography and assessed by enzyme-linked immunosorbent assay (ELISA). SERCA activity and calcium transport capability were determined by using colorimetric and radioisotopic methods. The mean ± standard deviation (SD) half maximal inhibitory concentration (IC50) of articaine was determined for each isoform, and these values were compared by using analysis of variance (ANOVA) (P < .05). Results: The native SERCA preparation consisted of 34% SERCA1a, 53% SERCA2a, 10% SERCA2b, and 3% combined SERCA3 and SERCA1b. Articaine caused inhibition of activity and calcium uptake in the native SERCA preparation and in each of the purified isoforms. The IC50 (mM) values for enzymatic activity were: SERCA1a 22.0 ± 2.3 > SERCA2a 16.4 ± 2.4 > SERCA2b 11.3 ± 1.9, and 15.1 ± 2.1 for native SERCA. For calcium transport, IC50 values were: SERCA1a 31.1 ± 3.3 > SERCA2a 24.8 ± 1.8 > SERCA2b 21.5 ± 1.5, and 25.2 ± 3.2 for native SERCA. IC50 values for inhibition of enzymatic activity were significantly different among the purified isoforms, but only the value obtained for SERCA1a was significantly different compared to native SERCA. For inhibition of calcium transport, IC50 values for both SERCA2a and SERCA2b differed significantly compared to SERCA1a, and the value for SERCA1a was significantly different compared to native SERCA. The most articaine-sensitive isoform was SERCA2b, and the native preparation showed sensitivity similar to SERCA2a. Conclusion: The differential inhibition of articaine on medial pterygoid SERCA isoforms is evident at concentrations lower than used in current dental practice (125 mM) and accounts for anesthetic myotoxicity. Muscle relaxation likely becomes impaired as a result of increased calcium levels in the myoplasm due to the decreased activity and calcium transport caused by the inhibition of SERCA.

Aims: To investigate the association between temporomandibular disorders (TMD) and rheumatoid arthritis (RA), as well as potential risk factors for TMD and the preventive effect of medications on TMD, by using the Taiwan National Health Insurance Research Database. Methods: In total, 17,317 patients newly diagnosed with RA and 17,317 matched controls without RA were followed up from 2000 to 2010. Cox regression was used to determine risk factors for developing TMD. Kaplan-Meier curve with log-rank test was used to determine the cumulative risk of TMD in RA patients and the effects of antirheumatic medications. Results: Cox regression showed a higher risk of developing TMD if patients had RA (adjusted hazard ratio [HR] 2.538, P < .001) and a lower risk if patients were of male gender and elderly (≥ 40 years) in comparison to younger patients (20 to 29 years) (P < .01). Patients with insomnia, stroke, and mental disorders had, respectively, 4.756, 6.929, and 9.671 times the number of events of TMD compared to those without diseases (P < .001). No patients with RA treated with disease-modifying antirheumatic drugs (DMARDs) developed TMD after the 11-year follow-up. Conclusion: RA patients had 2.538 times the events of TMD compared with non-RA patients during this trial in Taiwan. The other risk factors for developing TMD included female gender, younger age, insomnia, stroke, and mental disorders. The DMARDs had a beneficial effect on prevention of TMD.